diff --git a/crypto/modes/gcm_test.c b/crypto/modes/gcm_test.c
index 9414ac6..e543348 100644
--- a/crypto/modes/gcm_test.c
+++ b/crypto/modes/gcm_test.c
@@ -336,7 +336,7 @@
   }
 
   out = OPENSSL_malloc(plaintext_len);
-  if (out == NULL) {
+  if (plaintext_len != 0 && out == NULL) {
     goto out;
   }
   if (AES_set_encrypt_key(key, key_len*8, &aes_key)) {